gthread-posix.c revision b1d840c20a27dd756bd7bd5877631cb8acae1c62 
1/* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
3 *
4 * gthread.c: posix thread system implementation
5 * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
21 */
22
23/*
24 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
25 * file for a list of people on the GLib Team.  See the ChangeLog
26 * files for a list of changes.  These files are distributed with
27 * GLib at ftp://ftp.gtk.org/pub/gtk/.
28 */
29
30/*
31 * MT safe
32 */
33
34#include <pthread.h>
35#include <errno.h>
36#include <stdlib.h>
37#ifdef HAVE_SYS_TIME_H
38# include <sys/time.h>
39#endif
40#ifdef HAVE_UNISTD_H
41# include <unistd.h>
42#endif
43
44#ifdef HAVE_SCHED_H
45#include <sched.h>
46#endif
47
48#ifdef G_THREAD_USE_PID_SURROGATE
49# include <sys/resource.h>
50# define PID_IN_THREAD(thread) (*(pid_t*)(((gchar*)thread)+sizeof(pthread_t)))
51# define SET_PRIO(pid, prio) 						\
52  posix_check_cmd_prio ((setpriority (PRIO_PROCESS, (pid),		\
53		               g_thread_priority_map [prio]) == -1) ? 	\
54			          (errno == EACCES ? EPERM : errno ): 0)
55#endif /* G_THREAD_USE_PID_SURROGATE */
56
57#define posix_check_err(err, name) G_STMT_START{			\
58  int error = (err); 							\
59  if (error)	 		 		 			\
60    g_error ("file %s: line %d (%s): error '%s' during '%s'",		\
61           __FILE__, __LINE__, G_GNUC_PRETTY_FUNCTION,			\
62           g_strerror (error), name);					\
63  }G_STMT_END
64
65#define posix_check_cmd(cmd) posix_check_err (posix_error (cmd), #cmd)
66
67#ifdef G_ENABLE_DEBUG
68static gboolean posix_check_cmd_prio_warned = FALSE;
69# define posix_check_cmd_prio(cmd) G_STMT_START{			\
70    int err = posix_error (cmd);					\
71    if (err == EPERM)		 		 			\
72      { 	 			 				\
73        if (!posix_check_cmd_prio_warned) 		 		\
74          { 	 				 			\
75            posix_check_cmd_prio_warned = TRUE;		 		\
76            g_warning ("Priorities can only be changed " 		\
77                        "(resp. increased) by root."); 			\
78          }			 					\
79      }			 						\
80    else  		 						\
81      posix_check_err (err, #cmd);					\
82     }G_STMT_END
83#else /* G_ENABLE_DEBUG */
84# define posix_check_cmd_prio(cmd) G_STMT_START{			\
85    int err = posix_error (cmd);					\
86    if (err != EPERM)		 		 			\
87      posix_check_err (err, #cmd);					\
88     }G_STMT_END
89#endif /* G_ENABLE_DEBUG */
90
91#if defined(G_THREADS_IMPL_POSIX)
92# define posix_error(what) (what)
93# define mutexattr_default NULL
94# define condattr_default NULL
95#elif defined(G_THREADS_IMPL_DCE)
96# define posix_error(what) ((what) == -1 ? errno : 0)
97# define pthread_key_create(a, b) pthread_keycreate (a, b)
98# define pthread_attr_init(a) pthread_attr_create (a)
99# define pthread_attr_destroy(a) pthread_attr_delete (a)
100# define pthread_create(a, b, c, d) pthread_create (a, *b, c, d)
101# define mutexattr_default (pthread_mutexattr_default)
102# define condattr_default (pthread_condattr_default)
103#else /* neither G_THREADS_IMPL_POSIX nor G_THREADS_IMPL_DCE are defined */
104# error This should not happen. Contact the GLib team.
105#endif
106
107#ifdef G_THREAD_USE_PID_SURROGATE
108# define PRIORITY_LOW_VALUE 15
109# define PRIORITY_NORMAL_VALUE 0
110# define PRIORITY_HIGH_VALUE -15
111# define PRIORITY_URGENT_VALUE -20
112#elif defined (POSIX_MIN_PRIORITY) && defined (POSIX_MAX_PRIORITY)
113# define HAVE_PRIORITIES 1
114# define PRIORITY_LOW_VALUE POSIX_MIN_PRIORITY
115# define PRIORITY_URGENT_VALUE POSIX_MAX_PRIORITY
116#endif /* POSIX_MIN_PRIORITY && POSIX_MAX_PRIORITY */
117
118static gulong g_thread_min_stack_size = 0;
119
120#define G_MUTEX_SIZE (sizeof (pthread_mutex_t))
121
122#ifdef _SC_THREAD_STACK_MIN
123#define HAVE_G_THREAD_IMPL_INIT
124static void
125g_thread_impl_init()
126{
127  g_thread_min_stack_size = MAX (sysconf (_SC_THREAD_STACK_MIN), 0);
128}
129#endif /* _SC_THREAD_STACK_MIN */
130
131static GMutex *
132g_mutex_new_posix_impl (void)
133{
134  GMutex *result = (GMutex *) g_new (pthread_mutex_t, 1);
135  posix_check_cmd (pthread_mutex_init ((pthread_mutex_t *) result,
136				       mutexattr_default));
137  return result;
138}
139
140static void
141g_mutex_free_posix_impl (GMutex * mutex)
142{
143  posix_check_cmd (pthread_mutex_destroy ((pthread_mutex_t *) mutex));
144  g_free (mutex);
145}
146
147/* NOTE: the functions g_mutex_lock and g_mutex_unlock may not use
148   functions from gmem.c and gmessages.c; */
149
150/* pthread_mutex_lock, pthread_mutex_unlock can be taken directly, as
151   signature and semantic are right, but without error check then!!!!,
152   we might want to change this therefore. */
153
154static gboolean
155g_mutex_trylock_posix_impl (GMutex * mutex)
156{
157  int result;
158
159  result = pthread_mutex_trylock ((pthread_mutex_t *) mutex);
160
161#ifdef G_THREADS_IMPL_POSIX
162  if (result == EBUSY)
163    return FALSE;
164#else /* G_THREADS_IMPL_DCE */
165  if (result == 0)
166    return FALSE;
167#endif
168
169  posix_check_err (posix_error (result), "pthread_mutex_trylock");
170  return TRUE;
171}
172
173static GCond *
174g_cond_new_posix_impl (void)
175{
176  GCond *result = (GCond *) g_new (pthread_cond_t, 1);
177  posix_check_cmd (pthread_cond_init ((pthread_cond_t *) result,
178				      condattr_default));
179  return result;
180}
181
182/* pthread_cond_signal, pthread_cond_broadcast and pthread_cond_wait
183   can be taken directly, as signature and semantic are right, but
184   without error check then!!!!, we might want to change this
185   therfore. */
186
187#define G_NSEC_PER_SEC 1000000000
188
189static gboolean
190g_cond_timed_wait_posix_impl (GCond * cond,
191			      GMutex * entered_mutex,
192			      GTimeVal * abs_time)
193{
194  int result;
195  struct timespec end_time;
196  gboolean timed_out;
197
198  g_return_val_if_fail (cond != NULL, FALSE);
199  g_return_val_if_fail (entered_mutex != NULL, FALSE);
200
201  if (!abs_time)
202    {
203      g_cond_wait (cond, entered_mutex);
204      return TRUE;
205    }
206
207  end_time.tv_sec = abs_time->tv_sec;
208  end_time.tv_nsec = abs_time->tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
209  g_assert (end_time.tv_nsec < G_NSEC_PER_SEC);
210  result = pthread_cond_timedwait ((pthread_cond_t *) cond,
211				   (pthread_mutex_t *) entered_mutex,
212				   &end_time);
213
214#ifdef G_THREADS_IMPL_POSIX
215  timed_out = (result == ETIMEDOUT);
216#else /* G_THREADS_IMPL_DCE */
217  timed_out = (result == -1) && (errno = EAGAIN);
218#endif
219
220  if (!timed_out)
221    posix_check_err (posix_error (result), "pthread_cond_timedwait");
222  return !timed_out;
223}
224
225static void
226g_cond_free_posix_impl (GCond * cond)
227{
228  posix_check_cmd (pthread_cond_destroy ((pthread_cond_t *) cond));
229  g_free (cond);
230}
231
232static GPrivate *
233g_private_new_posix_impl (GDestroyNotify destructor)
234{
235  GPrivate *result = (GPrivate *) g_new (pthread_key_t, 1);
236  posix_check_cmd (pthread_key_create ((pthread_key_t *) result, destructor));
237  return result;
238}
239
240/* NOTE: the functions g_private_get and g_private_set may not use
241   functions from gmem.c and gmessages.c */
242
243static void
244g_private_set_posix_impl (GPrivate * private_key, gpointer value)
245{
246  if (!private_key)
247    return;
248  pthread_setspecific (*(pthread_key_t *) private_key, value);
249}
250
251static gpointer
252g_private_get_posix_impl (GPrivate * private_key)
253{
254  if (!private_key)
255    return NULL;
256#ifdef G_THREADS_IMPL_POSIX
257  return pthread_getspecific (*(pthread_key_t *) private_key);
258#else /* G_THREADS_IMPL_DCE */
259  {
260    void* data;
261    posix_check_cmd (pthread_getspecific (*(pthread_key_t *) private_key,
262					  &data));
263    return data;
264  }
265#endif
266}
267
268#ifdef G_THREAD_USE_PID_SURROGATE
269struct proxy_data
270{
271  GThreadFunc thread_func;
272  gpointer arg;
273  gpointer thread;
274  GThreadPriority priority;
275};
276
277static void
278g_thread_create_posix_impl_proxy (struct proxy_data *data)
279{
280  GThreadFunc thread_func = data->thread_func;
281  GThreadFunc arg = data->arg;
282  PID_IN_THREAD (data->thread) = getpid();
283  SET_PRIO (PID_IN_THREAD (data->thread), data->priority);
284  g_free (data);
285  thread_func (arg);
286}
287#endif /* G_THREAD_USE_PID_SURROGATE */
288
289static void
290g_thread_create_posix_impl (GThreadFunc thread_func,
291			    gpointer arg,
292			    gulong stack_size,
293			    gboolean joinable,
294			    gboolean bound,
295			    GThreadPriority priority,
296			    gpointer thread,
297			    GError **error)
298{
299  pthread_attr_t attr;
300  gint ret;
301
302  g_return_if_fail (thread_func);
303  g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
304  g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
305
306  posix_check_cmd (pthread_attr_init (&attr));
307
308#ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
309  if (stack_size)
310    {
311      stack_size = MAX (g_thread_min_stack_size, stack_size);
312      posix_check_cmd (pthread_attr_setstacksize (&attr, stack_size));
313    }
314#endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */
315
316#ifdef PTHREAD_SCOPE_SYSTEM
317  if (bound)
318    /* No error check here, because some systems can't do it and we
319     * simply don't want threads to fail because of that. */
320    pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
321#endif /* PTHREAD_SCOPE_SYSTEM */
322
323#ifdef G_THREADS_IMPL_POSIX
324  posix_check_cmd (pthread_attr_setdetachstate (&attr,
325          joinable ? PTHREAD_CREATE_JOINABLE : PTHREAD_CREATE_DETACHED));
326#endif /* G_THREADS_IMPL_POSIX */
327
328#ifdef G_THREAD_USE_PID_SURROGATE
329  {
330    struct proxy_data *data = g_new (struct proxy_data, 1);
331    data->thread_func = thread_func;
332    data->arg = arg;
333    data->thread = thread;
334    data->priority = priority;
335    PID_IN_THREAD (thread) = 0;
336    ret = posix_error (pthread_create (thread, &attr, (void* (*)(void*))
337				       g_thread_create_posix_impl_proxy,
338				       data));
339  }
340#else /* G_THREAD_USE_PID_SURROGATE */
341# ifdef HAVE_PRIORITIES
342#  ifdef G_THREADS_IMPL_POSIX
343  {
344    struct sched_param sched;
345    posix_check_cmd (pthread_attr_getschedparam (&attr, &sched));
346    sched.sched_priority = g_thread_priority_map [priority];
347    posix_check_cmd_prio (pthread_attr_setschedparam (&attr, &sched));
348  }
349#  else /* G_THREADS_IMPL_DCE */
350  posix_check_cmd_prio
351    (pthread_attr_setprio (&attr, g_thread_priority_map [priority]));
352#  endif /* G_THREADS_IMPL_DCE */
353# endif /* HAVE_PRIORITIES */
354  ret = posix_error (pthread_create (thread, &attr,
355				     (void* (*)(void*))thread_func, arg));
356#endif /* !G_THREAD_USE_PID_SURROGATE */
357
358  posix_check_cmd (pthread_attr_destroy (&attr));
359
360  if (ret == EAGAIN)
361    {
362      g_set_error (error, G_THREAD_ERROR, G_THREAD_ERROR_AGAIN,
363		   "Error creating thread: %s", g_strerror (ret));
364      return;
365    }
366
367  posix_check_err (ret, "pthread_create");
368
369#ifdef G_THREADS_IMPL_DCE
370  if (!joinable)
371    posix_check_cmd (pthread_detach (thread));
372#endif /* G_THREADS_IMPL_DCE */
373}
374
375static void
376g_thread_yield_posix_impl (void)
377{
378  POSIX_YIELD_FUNC;
379}
380
381static void
382g_thread_join_posix_impl (gpointer thread)
383{
384  gpointer ignore;
385  posix_check_cmd (pthread_join (*(pthread_t*)thread, &ignore));
386}
387
388static void
389g_thread_exit_posix_impl (void)
390{
391  pthread_exit (NULL);
392}
393
394static void
395g_thread_set_priority_posix_impl (gpointer thread, GThreadPriority priority)
396{
397  g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
398  g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
399#ifdef HAVE_PRIORITIES
400# ifdef G_THREADS_IMPL_POSIX
401  {
402    struct sched_param sched;
403    int policy;
404    posix_check_cmd (pthread_getschedparam (*(pthread_t*)thread, &policy,
405					    &sched));
406    sched.sched_priority = g_thread_priority_map [priority];
407    posix_check_cmd_prio (pthread_setschedparam (*(pthread_t*)thread, policy,
408						 &sched));
409  }
410# else /* G_THREADS_IMPL_DCE */
411  posix_check_cmd_prio (pthread_setprio (*(pthread_t*)thread,
412					 g_thread_priority_map [priority]));
413# endif
414#elif defined (G_THREAD_USE_PID_SURROGATE)
415  /* If the addressed thread hasn't yet been able to provide it's pid,
416   * we ignore the request. Should be more than rare */
417  if (PID_IN_THREAD (thread) != 0)
418    SET_PRIO (PID_IN_THREAD (thread), priority);
419#endif /* G_THREAD_USE_PID_SURROGATE */
420}
421
422static void
423g_thread_self_posix_impl (gpointer thread)
424{
425  *(pthread_t*)thread = pthread_self();
426#ifdef G_THREAD_USE_PID_SURROGATE
427  PID_IN_THREAD (thread) = getpid();
428#endif /* G_THREAD_USE_PID_SURROGATE */
429}
430
431static GThreadFunctions g_thread_functions_for_glib_use_default =
432{
433  g_mutex_new_posix_impl,
434  (void (*)(GMutex *)) pthread_mutex_lock,
435  g_mutex_trylock_posix_impl,
436  (void (*)(GMutex *)) pthread_mutex_unlock,
437  g_mutex_free_posix_impl,
438  g_cond_new_posix_impl,
439  (void (*)(GCond *)) pthread_cond_signal,
440  (void (*)(GCond *)) pthread_cond_broadcast,
441  (void (*)(GCond *, GMutex *)) pthread_cond_wait,
442  g_cond_timed_wait_posix_impl,
443  g_cond_free_posix_impl,
444  g_private_new_posix_impl,
445  g_private_get_posix_impl,
446  g_private_set_posix_impl,
447  g_thread_create_posix_impl,
448  g_thread_yield_posix_impl,
449  g_thread_join_posix_impl,
450  g_thread_exit_posix_impl,
451  g_thread_set_priority_posix_impl,
452  g_thread_self_posix_impl
453};
454